Owens “Lake”15,000 years ago, huge glaciers carved great valleys through California’s Sierra Nevada

Owens “Lake”15,000 years ago, huge glaciers carved great valleys through California’s Sierra Nevada Mountain range. Moisture from the Pacific Ocean is rung out of the air as snow that falls at the range’s peak, causing glaciers to flow both east and west from the crest of the range.East of the Sierra Nevada sits Owens Valley, which receives very little rain because of the mountain range in the way. When the mountains were filled with glaciers, meltwater from those ice sheets fed huge streams and lakes that flooded the low ground from Owens Valley all the way to Death Valley.Once the glaciers departed, Owens Valley converted into mostly a desert. It receives very little rain, but some streams are fed from snows and rains in the mountains. One of these, Owens River, flowed downhill from the tip of Owens Valley to a flat basin where it formed a lake known as Owens Lake.That all changed in the early 20th century. The city of Los Angeles constructed an aqueduct that took the water flowing into Owens Lake, causing the lake to rapidly dry up.Earlier we covered Iran’s lake Urmia, a brewing natural disaster that has shrunk by 88% in the last few decades (http://on.fb.me/1BvJUjE). After the city of Los Angeles took the water, Owens Lake completely dried up. As a consequence, all of the fine, salt-encrusted particles at the lake bottom were exposed to the wind and many were picked up, turning strong winds turned into dust storms.In the 1970s, the United States passed the “Clean Air Act”, placing limits on air pollution, including particulate air pollution like that generated by an artificially dried lake bed. The Clean Air Act actually forced Los Angeles to act.Starting in the late 1990s, small amounts of water were diverted back to Owens Lake, keeping the flat lakebed partially flooded and shutting down the dust storms. The presence of thin, salty layers of water have allowed algae to grow, turning the evaporation ponds red in many of the photos.The environmental disaster that was Owens Lake has been partially contained, but the mountain lake that used to sit on this site will never come back. Something like Owens Lake may be the end result of many drying lakes around the world; kept just wet enough to prevent dust from blowing, but without enough water to create a vibrant ecosystem.-JBBImage credits:https://flic.kr/p/992v8Khttp://bit.ly/1B1vgxXhttp://bit.ly/1zF06RDRead more:http://www.epa.gov/region9/air/owens/history.htmlhttp://geochange.er.usgs.gov/sw/impacts/geology/owens/http://www.desertusa.com/desert-california/owenslake.htmlhttp://www.owenslakeproject.com/Live webcam: http://www.gbuapcd.org/dustcam.htm -- source link

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